AIDS (acquired immunodeficiency syndrome) is a disease that makes it difficult for the body to fight off infectious diseases. The human immunodeficiency virus (HIV) causes AIDS by infecting and damaging part of the body's defenses against infection — its lymphocytes, which are white blood cells in the immune (infection-fighting) system that are supposed to fight off invading germs.

HIV can be transmitted through direct contact with the blood or body fluid of someone who is infected with the virus. That contact usually comes from sharing needles or by having unprotected sex with an infected person. An infant could get HIV from a mother who is infected.

HIV and AIDS can be treated, but there are no vaccines or cures for them.

What HIV Does to the Body

The virus attacks specific lymphocytes called T helper cells (also known as T-cells), takes them over, and multiplies. This destroys more T-cells, which damages the body's ability to fight off invading germs and disease.

When the number of T-cells falls to a very low level, people with HIV become more susceptible to other infections and they may get certain types of cancer that a healthy body would normally be able to fight off. This weakened immunity (or immune deficiency) is known as AIDS and can result in severe life-threatening infections, some forms of cancer, and the deterioration of the nervous system.

Although AIDS is always caused by an HIV infection, not everyone with HIV has AIDS. In fact, some adults who become infected with HIV may appear healthy for years before developing AIDS.

How Common Is HIV/AIDS?

The first case of HIV was reported in 1981, but the disease may have existed unrecognized for many years before that. HIV infection leading to AIDS has been a major cause of illness and death among children, teens, and young adults worldwide.

In recent years, HIV infection rates have been increasing rapidly among teens and young adults. Half of all new HIV infections in the United States occur in people under 25 years old; thousands of teens acquire new HIV infections each year. Most new HIV cases in younger people are transmitted through unprotected sex; one third are from injected drug usage via the sharing of dirty, blood-contaminated needles.

Among children, most cases of HIV infections resulted from transmission of the HIV virus from the mother to her child during pregnancy or birth, or through breastfeeding. In rare cases children may have been infected by being sexually abused by someone living with HIV.

Fortunately, medicines currently given to HIV-positive pregnant women have drastically reduced mother-to-child HIV transmission in the United States. These drugs are also used to slow or reduce some of the effects of the disease in people who are already infected.

But these medicines have not been readily available worldwide, particularly in the poorer nations hardest hit by the epidemic. Providing access to these life-saving treatments has become an issue of global importance.

How HIV Is Transmitted

HIV is transmitted through direct contact with the blood or body fluid of someone who is infected with the virus.

The three main ways HIV is passed to a very young child are:

while the baby develops in the mother's uterus (intrauterine)

at the time of birth

during breastfeeding

Among teens, the virus is most commonly spread through:

unprotected sex (oral, vaginal, or anal sex)

sharing needles used to inject drugs or other substances (including contaminated needles used for injecting steroids and tattooing and body art)

In very rare cases, HIV has also been transmitted by direct contact with an open wound of an infected person (the virus may be introduced through a small cut or tear on the body of the healthy person) and through blood transfusions. Since 1985, the U.S. blood supply has been carefully screened for HIV.

Signs and Symptoms of HIV

Although there may be no immediate physical signs of HIV infection at birth, if untreated, they might appear within 2 to 3 months after a child is born. Kids who are born with HIV can develop opportunistic infections, which are illnesses that can develop in weakened immune systems, such as Pneumocystisjirovicii pneumonia (PCP).

An untreated child with HIV may also get more severe bouts of other common childhood infections, such as Epstein-Barr virus (EBV) infection, which generally causes mild illness in most kids. In developing countries, tuberculosis has been a particularly common problem and often the cause of death of children and adults living with HIV.

Teens and young adults who contract HIV usually show no symptoms at the time of infection. In fact, it may take up to 10 years or more for symptoms to show. During this time, they can pass on the virus without even knowing they have it themselves. Once the symptoms of AIDS appear, they can include rapid weight loss, intense fatigue, swollen lymph nodes, persistent diarrhea, night sweats, or pneumonia. They, too, will be susceptible to life-threatening opportunistic infections.

Diagnosing HIV Infections and AIDS

Every pregnant woman should be tested for HIV to have a better chance of preventing transmission to her unborn child.

If a woman knows she is HIV-infected and already has children, it is recommended that all of them be tested for HIV. Even older kids who seem healthy could still have an HIV infection if she was HIV-positive at the time they were born. A blood test is needed to know for sure.

Newer tests can help doctors to determine if a baby born to an HIV positive mother is infected in the first few months of life.

Older kids, teens, and adults are tested for HIV infection by a number of different tests that look for antibodies to the virus, proteins that coat the virus, or the presence of the virus itself. Antibodies are specific proteins that the body produces to fight infections; HIV-specific antibodies are produced in response to infection with HIV. Someone with antibodies against HIV is said to be HIV-positive.

If any one of the tests is positive, it will be repeated or confirmed with another test.

Can Kids Spread HIV?

Across the United States, only a handful of cases have been reported where HIV infection was contagious from a child to another person. All of those cases involved direct blood contact within a household. The typical baby secretions (urine, drool, spit up, vomit, feces, etc.) do not seem to transmit the virus, so routine care of babies with HIV is considered safe.

Despite widespread concerns, no transmissions of HIV within a school or childcare setting have been reported. Because the danger in transmitting HIV involves direct contact with blood, personnel at schools and childcare programs should routinely use gloves when any child has a cut, scrape, or is bleeding.

Transmission of HIV Among Teens

Among teens, HIV is spread mostly through unprotected sex with an infected person or sharing intravenous drug needles. Education of children and teens is vitally important to help prevent sexual transmission of HIV, as well as other sexually transmitted diseases (STDs), including chlamydia, genital herpes, gonorrhea, hepatitis B, syphilis, and HPV (which can cause genital warts or lead to various cancers).

Many STDs cause irritation, sores, or ulcers of the skin and mucous membranes that the virus can pass through. Having an STD, such as genital herpes, for example, has been proven to increase the risk of getting HIV if the person has unprotected sex with someone who is HIV-positive.

Opportunistic Infections

Opportunistic infections (infections that take advantage of a person's weakened immune system) are the most common complication of HIV/AIDS.

Sometimes adults with HIV/AIDS can get an infection from germs that do not normally cause illness in a healthy person (like cryptococcus). People with AIDS (especially children) can get a severe version of a more common infection, such as chickenpox.

These opportunistic infections and conditions can frequently occur in kids with HIV:

viral infections, such as a form of chronic walking pneumonia called lymphoid interstitial pneumonia (LIP), herpes simplex virus, shingles, and the cytomegalovirus infection

parasitic infections, such as PCP (a pneumonia caused by Pneumocystis jirovicii, a microscopic parasite that can't be fought off due to a weakened immune system) and toxoplasmosis

fungal infections, such as esophagitis (inflammation of the esophagus), and candidiasis or thrush (yeast infection)

Other Complications

Children with HIV are also at higher risk for some forms of cancer because of their weakened immune systems. Lymphomas associated with Epstein-Barr virus (EBV) infection are more common in older kids with HIV.

Difficult complications in treating kids who have HIV/AIDS include the wasting syndrome (the inability to maintain body weight due to long-term poor appetite and other infections related to HIV disease) and HIV encephalopathy (due to HIV infection of the brain that causes swelling and then damage to the brain's tissues over time).

HIV encephalopathy can result in dementia, especially in adults. Wasting syndrome can sometimes be helped with nutritional counseling and daily high-calorie supplements, but preventing HIV encephalopathy remains extremely difficult.

Treating HIV/AIDS

The last 20 years have brought two major developments in the treatment of HIV/AIDS:

drugs that inhibit the virus's growth, preventing or delaying the onset of AIDS and allowing people with HIV to remain free of symptoms longer

drugs that help reduce the transmission of the virus from an HIV-infected mother to her child

As medical understanding about how the virus invades the body and multiplies within cells increases, drugs to inhibit its growth and slow its spread are developed. Drug treatment for HIV/AIDS is complicated and expensive, but highly effective in slowing the replication (reproduction) of the virus and preventing or reducing some effects of the disease.

Drugs to treat HIV/AIDS use several different strategies, including:

interfering with HIV's reproduction of its genetic material (called nucleoside or nucleotide anti-retrovirals)

interfering with the enzymes HIV needs to take over certain body cells (these drugs are called protease inhibitors)

interfering with HIV's ability to pack its genetic material into viral code — that is, the genetic "script" HIV needs to be able to reproduce itself. These medicines are called non-nucleoside reverse transcriptase inhibitors (NNRTIs).

newer types of medications (integrase inhibitors and CCR5 inhibitors) that use different strategies

Because these drugs work in different ways, doctors generally prescribe a "combination cocktail" of these drugs that is taken every day. This regimen is known as HAART (highly active anti-retroviral therapy) treatment. Doctors also may prescribe drugs to prevent certain opportunistic infections when a person's immune system is very weak — for example, some antibiotics can help prevent PCP, especially in kids.

A number of medicines can treat HIV infection and slow the onset of AIDS, but they must be taken and administered properly on a round-the-clock schedule. Otherwise, the virus can quickly become resistant to that particular "cocktail."

HIV is very adaptable and finds ways to outsmart medical treatments that are not followed properly. This means that if prescribed medicines are not taken at the correct times every day, they will soon fail to keep HIV from reproducing and taking over the body. When that happens, a new regimen must be established with different drugs. And if this new mix of medicines is not taken correctly, the virus will likely become resistant to it, too, and eventually the person will run out of treatment options.

Aside from the difficulty of getting young children to take their medication on a timed schedule, the medications present other problems. Some have unpleasant side effects, such as a bad flavor, whereas others are only available in pill form, which may be difficult for kids to swallow.

Parents who need to give their child these medications can ask the doctor or pharmacist for suggestions on making them easier to take. Many pharmacies can add flavoring to bad-tasting medicines or your doctor may recommend mixing pills with applesauce or pudding.

Because drug options are still limited, doctors are concerned that if children fail to take their medicines as prescribed (even missing just a few doses), the virus could eventually develop resistance to the existing HIV drugs — making treatment difficult or impossible. So it is very important that kids take their medications as directed.

One of the most important home treatment messages for any parent or caregiver is that the child should take all medications consistently, at the time the prescription indicates. This can be difficult — but many HIV/AIDS family support groups and experienced medical providers can offer practical suggestions to help families be successful with the day-to-day challenges they face.

Many of the new medications that fight HIV infection are very expensive. In the United States, special programs can pay for medicine for all HIV-positive kids. Unfortunately, many people don't have access to these medicines in other parts of the world, especially in developing countries.

Preventing Mother-to-Child Transmission of HIV

When a pregnant HIV-infected woman receives good medical care early and takes antiviral medications regularly during her pregnancy, the chance that she will pass HIV to her unborn baby is dramatically reduced.

It is important that any pregnant woman who knows she is HIV-positive start prenatal care as soon as possible to take full advantage of such treatments. The sooner a mother receives treatment, the greater the likelihood her baby will not get HIV.

An HIV-infected mother can receive medical treatment:

before the birth of her baby: antiviral treatments given to the mother during pregnancy can help prevent HIV transmission to the baby

at the time of birth: antiviral medications can be given to both the mother and the newborn to lower the risk of HIV transmission that can occur during the birth process (which exposes the newborn to the mother's blood and fluids); in addition, the mother will be encouraged to formula-feed rather than breastfeed because HIV can be transmitted to her baby through breast milk

during breastfeeding: because breastfeeding is discouraged among HIV-infected mothers, this type of transmission is rare in the United States. However, in places in the world with limited access to formula or a clean water supply to mix it, both the mother and child can be treated with medication to lower the baby's risk of HIV infection.

Before antiviral medicines were routinely given, almost 25% of children born to HIV-infected mothers developed the disease and died by 24 months of age. Now, studies show that mothers with HIV who get good prenatal care and regularly take antiviral drugs during their pregnancy have less than a 1% chance of passing HIV to their babies. If these babies do get the HIV virus, they tend to be born with a lower viral load (less HIV virus is present in their bodies) and have a better chance of long-term, disease-free survival.

Long-Term Care of Kids With HIV/AIDS

Cases of HIV infection and AIDS in children are complicated and should be managed by experienced health care professionals. Kids will need to have their treatment schedules closely monitored and adjusted regularly. Any infections that could become life threatening must be quickly recognized and treated.

Medicines are adjusted in relation to the child's viral load. The child's health is also monitored by frequent measurement of T-cell levels because these are the cells that the HIV virus destroys. A good T-cell count is a positive sign that medical treatments are working to keep the disease under control.

Kids should see their health care providers often for blood work, physical exams, and discussions about how they and their families are coping socially with any stress from their disease.

Some immunizations during routine visits may be slightly different for infants or children with HIV/AIDS. A child whose immune system is severely compromised will not receive live virus vaccines such as measles-mumps-rubella (MMR) and varicella (chickenpox). All other routine immunizations are given as usual, and a yearly influenza vaccine (flu shot) is recommended.

If a family seeks health care in a hospital emergency department, parents should be sure to tell the nurse who registers the child that the child has HIV. This will alert medical caregivers to look closely for any signs of diseases from opportunistic infections and provide the best possible treatment.

Outlook for HIV/AIDS

There is no vaccine to prevent HIV and AIDS, although researchers are working to develop one. Combinations of antiviral drugs and drugs that boost the immune system have allowed many people with HIV to resist infections, stay healthy, and live longer, and many children born with HIV who are treated early reach adulthood.

Preventing HIV and AIDS

Prevention of HIV remains of worldwide importance. Despite much research, there is no vaccine that will prevent HIV infection. Infection can be prevented by never sharing needles, and abstaining from oral, vaginal, or anal sex. Since most people will eventually become sexually active at some point in their lives, always using condoms for all types of sexual intercourse can drastically reduce the risk of getting HIV.

Testing all pregnant women multiple times during pregnancy can also help. If the result is positive, immediate treatment can begin before the baby is born to prevent HIV transmission.

Talking With Kids About HIV/AIDS

Talking about HIV/AIDS means talking about sex and drugs — and it's not always easy for parents to talk about sexual feelings and behavior with their kids. Similarly, it's not always easy for teens to open up or to believe that issues like HIV/AIDS can affect them.

Doctors and counselors suggest that parents become knowledgeable and comfortable discussing sex and other difficult issues early on, even before the teen years. After all, the issues involved — understanding the body and sexuality, adopting healthy behaviors, respecting others, and dealing with feelings — are topics that have meaning at all ages (though how parents talk with their kids will vary according to a child's age and ability to understand). Open communication and good listening skills are vital.

Doctors, teachers and counselors can help. Many schools provide age-appropriate information about HIV/AIDS that has been designed to educate kids about the disease. Studies show that such education makes a tremendous difference in preventing risk behaviors in young people. Pediatricians, adolescent medicine specialists, and family doctors can also help you feel comfortable about talking to your kids and will also spend time talking to your child about how to be safe and prevent HIV infection.

Ultimately, parents who are well-informed about how to prevent HIV and who talk with their kids regularly about healthy behaviors, feelings, and sexuality can make a huge difference in preventing HIV infection and helping kids to grow up to become healthy adults.